A small piece of burning or glowing coal or wood in a dying fire. The campfire had burned down to a few glowing embers.
The smouldering remains or glowing ashes of a fire. They warmed their hands over the embers of the previous night's blaze.
Figurative: a small remaining but still potent part of a once-strong feeling, idea, or movement. The embers of the revolution still burned in their hearts.